Organometallic complex catalysts have very high utility and potential in the field of organic synthesis chemistry and have found use in cross-coupling reactions which are essential for the development of products such as functional molecules and medicines. The selectivity and the catalytic activity of the metal complex catalysts depend on “ligands” which are coordinated to metals. Because there are no general-purpose ligands exhibiting excellent stereoselectivity and reaction activity in all catalytic reactions, it is necessary that characteristic ligands be identified in order to develop useful catalytic reactions.
Phosphines and arsines are conventional ligands widely used in transition metal complexes. For example, chiral diphosphine compounds represented by BINAP [(1,1-binaphthalene)-2,2-diylbis(diphenylphosphine)] and MeO-BIPHEP [(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine)] are used very widely as chiral ligands in optically active transition metal complexes utilized as asymmetric synthesis catalysts.
The present inventors have developed chiral ligands 1a and 1b represented by the formulae below (Patent Literature 1, Non Patent Literatures 1 to 3). Of these ligands, the chiral ligand 1b is “highly electron-deficient”, which is an unprecedented characteristic in chiral diphosphine ligands, and is a very promising ligand that can give metal catalysts capable of catalyzing an asymmetric 1,4-addition reaction with high enantioselectivity and with the world's highest activity achieved in catalytic asymmetric carbon-carbon bond formation reactions.
